Remove rtsol(8) from rc.d/network. Add -w seconds command to ifconfig to wait for N seconds for until DAD has finished on all addresses. Use ifconfig -w in rc.d/network instead of a forced sleep. As discussed on tech-net@
MKINET6 is for providing IPv6 infrastructure. USE_INET6 is for compiling IPv6 support into the programs (needs MKINET6).